More air equals more power! Stock Air Filtration on Wranglers is restrictive. Rock-It Hi-Flow filters flow an average of 50% more air in the same filtration area over stock. These Hi-Flow filters have over 77 square inches of filtration area. Not only do these flow more air, but they catch finer particles and are completely washable & reusable with the optional Filter Re-Charger Kit. The Max-Flow filter has even greater surface area, allowing 10% more air flow over the Hi-Flow element, and is better suited for dusty trail riding. Both Hi-Flow & Max-Flow Systems are warranted for one million miles. The Intake tubes feature smoother bends, better transitions and a larger diameter to allow a significantly greater airflow, which adds up to 6 more horsepower. The Optional Outerwares Pre-Filter is recommended for extremely dusty off road abuse. Made from durable fine mesh polyester material to filter .005" debris. Pre-Filters may be washed with soap & water.Not CARB certified and not for use in the state of California. Check your local laws and regulations before purchasing.